SAN FRANCISCO — Low-income Californians who are elderly and disabled were less likely to go to the emergency room or be hospitalized after their in-home caregivers participated in an intensive training program, according to a report.

Under a pilot program, nearly 6,000 aides in Contra Costa, Los Angeles and San Bernardino counties were trained in CPR and first aid, as well infection control, medications, chronic diseases and other areas. All were workers of the In-Home Supportive Services program, who are paid by the state to care for low-income seniors and people with disabilities, many of them relatives.

Researchers at the University of California, San Francisco based their analysis on the results in Contra Costa County, which they said produced the most complete and reliable data.

UCSF professor emeritus Bob Newcomer said they compared insurance claims on 136 at-risk elderly and disabled residents whose caregivers were trained with the claims from more than 2,000 similar residents whose caregivers did not receive the training. Though the sample was small, Newcomer said he was encouraged by the findings.

“Training shows a lot of promise,” he said.

The rate of repeated emergency room visits declined by 24 percent, on average, in the first year after caregivers were trained and 41 percent in the second year, according to the UCSF analysis.

The demand for in-home caregivers is rising as the population ages. But most caregivers, including those paid by the state, are not required to receive formal training even though many are looking after people who have chronic diseases, dementia or mental illness.

California’s supportive services program pays caregivers to help about half a million elderly and disabled people stay in their homes rather than be placed in institutions. To qualify for the care, seniors must be eligible for Medi-Cal, be 65 or older, and be blind or disabled.